where rot and div denote the rotation and the divergence respectively, E , D , H and B are the four vector quantities determining the electromagnetic field, J is the electric current density, ρ is the volumic electric charge and t is the time.

Note 2 – The Maxwell equations completely define the electromagnetic field in a given medium only together with the relations characterizing the medium, often called constitutive relations; in the case of a linear medium, these relations are expressed in terms of the permittivity, permeability, and conductivity of the medium.